function getElement() {

}
getElement.prototype = {
	getElem:function(id) {
		return document.getElementById(id);
	},
	//root:父节点的ID；str:class名；tag:class类的标签名
	getElems:function(root,str,tag) {
		if(root){
	        root=typeof  root=="string"?document.getElementById(root):root;
	    }else{
	        root=document.body;
	    }
	    tag=tag||"*";
	    var els=root.getElementsByTagName(tag);
	        arr=[];
	    for(var i= 0,n=els.length;i<n;i++){
	        k=els[i].className.split(" ");
	        l= k.length;
	        for(var j= 0;j<l;j++){
	            if(k[j]==str){
	                arr.push(els[i]);
	                break;
	            }
	        }
	    }
	    return arr;
	},
	getElemsByName:function(TagName) {
		return document.getElementsByTagName(TagName);
	},
	createElem:function(tagName) { 
		return document.createElement(tagName);
	},
	//获取url参数，使用说明，如：getQueryString("参数")
	getQueryString:function(name) { 
		var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i"); 
		var r = window.location.search.substr(1).match(reg); 
		if (r != null) return unescape(r[2]); return null; 
	}

}
